This invention relates to recording tape or film; and more particularly to self-tracking recording tape or film.
The recording industry, particularly the magnetic tape recording industry, has in relatively recent years become a large and continually expanding industry. Available on today's market are magnetic recording tape systems ranging from complex systems utilized in computers or with other industrial or business applications down to relatively simple systems utilized for home entertainment or other purposes. Since the first magnetic tape system appeared on the market, the industry has continually improved the systems. For example, better tapes have been produced, better heads and better head shields have been designed, and the transport systems have been vastly improved. In addition, tremendous strides have been made in reducing the size, weight and cost of these magnetic recording systems. In more recent times, the industry has been striving to increase the number of tracks that can be provided on a given tape width. As the packing density on a given tape is increased, the need for more accurate alignment of the tracks with respect to the head also increases. Without this accurate alignment, cross talk and distortion will occur.
Many of today's magnetic tape recording systems utilize an edge guide to align the tape properly with respect to the head. Today's magnetic tapes are extremely thin; therefore, a very small surface of the tape is used to guide the tape in these edge guide systems. Further, the edge of the tape becomes worn from rubbing against the edge guide; and therefore, the edge of the tape becomes increasingly less reliable as a guide. After repeated usage of the tape, the edge of the tape may become so worn that the tape will no longer be accurately aligned with respect to the head or heads. This is particularly true where a large number of tracks are provided on a given tape. When the tracks are no longer properly aligned with the head gap or head gaps, distortion occurs. In addition to the wear problem, the edge guide alignment systems are limited in the degree of accuracy of alignment that such a guide system can provide since a very small portion of the tape is actually used for guide purposes.
As has been mentioned above, the problem of providing accurate tracking increases as the packing density increases since a higher degree of accuracy is required when a large number of tracks are provided on a given width of tape. However, accurate tracking is also required when there are but a few tracks on a given tape width since improper tracking, even in this instance, will cause distortion or possibly cross talk. While the above discussion has been directed to magnetic tapes and magnetic tape recording systems, accurate tracking is required in any tape or film recording system. Thus, this problem of providing accurate tracking is not one that is exclusively related with magnetic tape recording systems and tape.
This invention provides a recording tape or film that is essentially self-tracking. In addition to the tape itself, this invention is directed to specifically designed tape reels, tape transport systems, and record-reproduce heads or transducers that are designed to accommodate the tape or film. With the tape or film, reels, transport mechanisms and heads designed in accordance with this invention, a high degree of tracking accuracy can be obtained; therefore, a large number of recording tracks can be provided on a given width of tape or film.